The present invention relates to a method and apparatus for separating water from oil.
Oils are prone to be strongly invaded by water from leaking coolers, condensate in reservoirs, cleaning and steam leakages. Water may reduce viscosity, cause defects of the structural composition of the oil and disturb/destroy additives in the oil. This will result in an accelerating change of the oil (the oil forming water as a result of ageing) and bacterial growth and corrosion, resulting in reduced life of the oil and of the components in which it serves.
U.S. Pat. No. 5,211,856 discloses a method of separating water from oil, in which the oil to be separated is introduced in a heated condition at a predetermined temperature into a container subjected to a vacuum. Gas which is preheated to the temperature of the oil is introduced into the oil in the container to form gas bubbles rising through the oil while absorbing water vapor which, together with the gas in the bubbles, is released in the upper part of the column and withdrawn from the top thereof.
The object of the present invention is to provide a continuous separation process which, by means of a particularly simple and reliable apparatus, results in a higher efficiency than that of the above and other prior methods of this type. In other words, in a simple manner, the process enables larger amounts of water to be separated per unit time from a certain amount of oil. This object is achieved according to the invention, by a process and apparatus as defined in the claims.
Admittedly, it is a well-known technique to promote evaporation of a liquid by causing it to flow across a large surface area such as packing in a column. However, the present invention provides a surprisingly simple and effective manner of combining the two above-mentioned prior separating principles which, as far as the applicant knows, provides an unsurpassed efficiency in separating water from oil. The invention will also result in a correspondingly effective separation of air or other gaseous contaminations from the oil.